Improving Mercedes OM603 engine efficiency

[320touring]

Tonight, at an undisclosed location near Baurheid, the Merc met it's Nemesis..

THE PIT!


The Merc fears the pit as it exposes all its weaknesses.

The principal task was to stop the exhaust blowing as much.

Under I went


The news was not good..






However, I had a plan.
And it was a good plan.
Gungum and Exhaust bandage to the rescue!





The result?
It's not ****ting out veg fumes from all over the shop.
This pic was taken with it running



Hopefully that should help fuel consumption a bit too

[320touring]

Here's a quick look at the SVO/WVO the car is running on, along with a cold start in -3 degrees

https://youtu.be/nJaa1KDJReY

[320touring]

And so to the oil service.

After a run out to get scran in for lunch, the Merc was up to temp, and oil extraction could begin.

Don't tell Junkman, but this om603 takes 8!!!! Litres of 10w40 for an oil and filter change.

Whilst the PELA did it's thing (and keeping an eye on it, as it only holds 6L at a time!) I set to removing the oil filter.

First, it was bonnet to 'service' position, and then loosening the single 13mm bolt, and 2 13mm nuts holding the filter housing lid on.



The construction is similar to the filter housings on the BMW M30 engine, but much more over engineered.

The BMW only has a central 13mm bolt. It keeps pressure even round the top seal, so God knows why there are an additional 2 13mm nuts holding the filter lid on the Merc?

The 2 13mm nuts come off straight away, but the 13mm bolt needs unscrewing and removing to allow the lid off past the bulkhead.



The old filter was tired, and the stylish* Waffle construction of the lid can be seen.



Next step was cleaning out the filter housing And getting the new filter popped in . Marvel at the handle !



Once everything was buttoned back up, fresh 10w40 was poured in(Asda had it at £13 per 5L).

The old oil was popped into containers for later processing*.

The result?

Much quieter running - on the motorway at about 75-80mph at a light throttle, it sounds for all the world like a large capacity 6 cylinder petrol..

I'm growing to like this tub!

[320touring]

431.4 miles covered, 62.39L used (56L veg, 6.39 L Derv)
Giving 31.43mpg (imp)
26.17mpg (US)

[320touring]

Since the last fuelling (the first with some WVO in it) she has been grumpy to start.. OM603 non turbo

My thinking is filters (unknown how long they have been on) or the fuel mix isn't working - anyone any suggestions?

Video at link below

https://youtu.be/eDzjZb5pMxE

[Piotrsko]

Can it be thickening? Maybe some diesel 911 or related.

[320touring]

Originally Posted by Piotrsko

Can it be thickening? Maybe some diesel 911 or related.

The WVO does look fairly thick, and I think this car is missing a fuel heater.

drove it a mile up the road, did what I was doing (90mins passed) and it started fine first heat when I came to go back down the road.

[ratgreen]

Ive got a om606 merc I run on veg. In this temp I add 5-10% petrol to thin it out, as well as add 2ehn to raise the cetane back up.

om606 has a factory fuel/coolant heat exchanger build into the heads so I didnt have to worry. If yours doesnt I'd get one. I also have a 12v sillicone heating pad wrapped around my fuel filter to help warm it up before the engine has got to temp.

[320touring]

Originally Posted by ratgreen

Ive got a om606 merc I run on veg. In this temp I add 5-10% petrol to thin it out, as well as add 2ehn to raise the cetane back up.

om606 has a factory fuel/coolant heat exchanger build into the heads so I didnt have to worry. If yours doesnt I'd get one. I also have a 12v sillicone heating pad wrapped around my fuel filter to help warm it up before the engine has got to temp.

Mine should have a fuel heater, but as far as I know, it's been removed.. the joy of old cars with multiple owners and no service history

I may try something petrol in it if the filters have no impact.

Cheers

[320touring]

The last tank was 430.1miles to 67L - giving 24.3mpg US

This tank included a lot of town driving and a fair amount of cold starts (down to -6 Celsius).

It's not the worst, but definitely could be improved upon.

Being a heavy car with a tired autobox and low power, it feels like you are always accelerating - something I need to try and avoid.

With it being mechanical pump, I don't even get DFCO

Initial thoughts are:
Remove the extraneous junk/tools from the boot
Add a little more air to the tyres.
Work out the shift patterns of the gear box more effectively.

Longer term:
Autobox fluid and filter change
Diff oil service
Replace exhaust
Advance fuel pump timing (it alters as the chain wears, MB suggest 1-2 degrees for every 100k miles)